Browsing by Author "Xie, Zhong-Han"

Now showing 1 - 2 of 2

Slanted n-ZnO nanorod arrays/p-GaN light-emitting diodes with strong ultraviolet emissions
(2015-02-01)
Yang, Zu-Po
;
Xie, Zhong-Han
;
Lin, Chia-Ching
;
Lee, Ya-Ju
;
光電系統研究所
Both of oblique angle deposition and conventional deposition techniques were used by a RF sputtering system to grow the slanted (beta = 32 degrees) and planar (beta = 0 degrees) n-ZnO films on p-GaN, respectively. These two kinds of n-ZnO/p-GaN heterojunctions were then fabricated the light-emitting diodes (LEDs). The electrical and optical properties of these two kinds of LEDs were investigated systematically. The results show that the slanted n-ZnO/p-GaN LEDs have a lower turn-on voltage and less leakage current than that of planar n-ZnO/p-GaN LEDs. Moreover, different from the planar n-ZnO/p-GaN LEDs which emitting colors changes with injection current, the slanted n-ZnO/p-GaN LEDs retains UV emissions (385-400 nm) under the entire range of injection currents we applied. The dominant UV luminescence of slanted n-ZnO/p-GaN LEDs is attributed to the ZnO near band edge transitions, indicating the high quality of slanted ZnO films and exhibiting the essential property dedicated to nano-sized heterojunctions. Hence, we have demonstrated that the slanted n-ZnO/p-GaN LEDs fabricated by oblique angle deposition have better performance than the planar n-ZnO/p-GaN LEDs fabricated by convention deposition means. (C) 2015 Optical Society of America
Slanted n-ZnO/p-GaN nanorod arrays light-emitting diodes grown by oblique-angle deposition
(2014-05-01)
Lee, Ya-Ju
;
Yang, Zu-Po
;
Lo, Fang-Yuh
;
Siao, Jhih-Jhong
;
Xie, Zhong-Han
High-efficient ZnO-based nanorod array light-emitting diodes (LEDs) were grown by an oblique-angle deposition scheme. Due to the shadowing effect, the inclined ZnO vapor-flow was selectively deposited on the tip surfaces of pre-fabricated p-GaN nanorod arrays, resulting in the formation of nanosized heterojunctions. The LED architecture composed of the slanted n-ZnO film on p-GaN nanorod arrays exhibits a well-behaving current rectification of junction diode with low turn-on voltage of 4.7 V, and stably emits bluish-white luminescence with dominant peak of 390 nm under the operation of forward injection currents. In general, as the device fabrication does not involve passivation of using a polymer or sophisticated material growth techniques, the revealed scheme might be readily applied on other kinds of nanoscale optoelectronic devices. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.